"The powerful faction comprising militants from the Mehsud tribe — the core around which regional militant groups initially gravitated to form the TTP — said it was forming its own separate group called Tehrik Taliban South Waziristan.

"A spokesman for the new group, Azam Tariq Mehsud, told reporters the decision to part ways with the TTP was made when efforts to persuade the TTP leadership to give up practices which were 'contrary to Islam' failed.

" 'We consider the bombing of public places, extortion and kidnappings un-Islamic, and since the TTP leaders continued with these practices, we decided we should not share the responsibility,' he said."

The Guardian reports that the breakaway Mehsud tribe is "widely considered the most important of the various groups that comprise the umbrella Tehreek-e-Taliban Pakistan (TTP), which has fought the government since 2007 to implement its version of sharia law."

The Associated Press says the split underscores "the difficulty the U.S.-allied government will have in negotiating an end to a decade of violence with increasingly fragmented militant groups." However, The Guardian quotes "observers" as saying "the split [is] a victory for the Pakistan military's strategy of pitting militant factions against each other while gaining the loyalty of key commanders."